configure.ac: automatically find versioned servlet-api.jar
configure.ac: automatically find versioned servlet-api.jar

Change-Id: I87533bb16d0ac2bbcb7c8592c4f6caa1aa05c705

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core